Lol, you did disconnect the battery didn't you
Had a code you were trying to remove maybe? Yeti 1 and 2, computer told you you had another issue and you swept it under the rug. You didn't disclose the battery disconnect, assuming you knew it had to be hypermiling. There is a snake here allright
The ECU learns, not just the monitors, but also short and long term fuel air trims and other software peculiarities. The shortness of being reset (battery disconnect) can easily explain the difference.
Testing procedures also indicate variance from test to test in HCs, see the link.
If the tps were somewhat oxidized from lack of use, it could give a different reading after being used a bit more, maybe the ECU didn't think it was quite at idle the first time. Maybe the operator moved the gas pedal differently the second test. Who knows, too many variables here, don't jump to conclusions without eliminating some variables.
The high speed test was comparable though, so don't think you are automatically polluting a lot more in any event.
You are looking at a henhouse in the middle of a zoo full of open cages and you don't realize it. It is much to early to be blaming hypermiling for your observed results.